Tuberculosis-associated Immune Reconstitution Inflammatory Syndrome (TB-IRIS) is a common complication in HIV-TB co-infected patients receiving combined antiretroviral therapy (cART). While monocytes/macrophages play major roles in both HIV- and TB-infection individually, a putative contribution of monocytes to the development of TB-IRIS remains unexamined. We performed a genome-wide array analysis on MOs purified from peripheral blood mononuclear cells (PBMCs) obtained before initiation of combined antiretroviral therapy (cART) to verify whether the transcriptome of MOs was already significantly modulated (even before receiving cART) in HIV+/TB+ patients who later developed TB-IRIS compared to control HIV+/TB+ patients who did not develop the complication . The subjects under study included a subset of 18 TB-IRIS patients and controls matched for age, gender and CD4 count.